Field of the Disclosure
The present disclosure relates to couplings for an expandable tubular.
Description of the Related Art
In the oil and gas exploration and production industry, expandable tubing has been developed and has a variety of uses. Expandable tubing offers a number of advantages over conventional borehole tubing, as the expandable tubing can be run into a borehole in an unexpanded state and subsequently expanded downhole. This allows the tubing to be run through existing tubing and then expanded to a larger diameter within the borehole.
FIG. 1A illustrates a connection 1 between two expandable tubulars before expansion thereof. FIG. 1B illustrates the connection 1 after expansion. The expandable tubing sections typically include a male threaded portion (pin) 2p and a female threaded portion (box) 2b at opposite ends, for joining adjacent sections of tubing together end to end. A seal 3 is engaged with the box 2b, thereby providing a fluid-tight seal. However, upon expansion of the connection, plastic deformation of the seal-groove area may cause the area to sag as shown in FIG. 1B. The seal 3 then contracts into the sagged base, thereby disengaging from the box 2b. Disengagement of the seal compromises the sealing integrity of the connection during and after expansion.
There exists a need in the art for an expandable connection which maintains sealing integrity before, during, and after expansion.